Replication Guidelines and Considerations

When you use replication with Virtual Volumes, specific considerations apply.

You can apply the replication storage policy only to a configuration virtual volume and a data virtual volume. Other VM objects inherit the replication policy in the following way:

The memory virtual volume inherits the policy of the configuration virtual volume.

The digest virtual volume inherits the policy of the data virtual volume.

The swap virtual volume, which exists while a virtual machine is powered on, is excluded from replication.

If you do not apply the replication policy to a VM disk, the disk is not replicated.

The replication storage policy should not be used as a default storage policy for a datastore. Otherwise, the policy prevents you from selecting replication groups.

Replication preserves snapshot history. If a snapshot was created and replicated, you can recover to the application consistent snapshot.

You can replicate a linked clone. If a linked clone is replicated without its parent, it becomes a full clone.

If a descriptor file belongs to a virtual disk of one VM, but resides in the VM home of another VM, both VMs must be in the same replication group. If the VMs are located in different replication groups, both of these replication groups must be failed over at the same time. Otherwise, the descriptor might become unavailable after the failover. As a result, the VM might fail to power on.

In your Virtual Volumes with replication environment, you might periodically run a test failover workflow to ensure that the recovered workloads are functional after a failover.

The resulting test VMs that are created during the test failover are fully functional and suitable for general administrative operations. However, certain considerations apply:

All VMs created during the test failover must be deleted before the test failover stops. The deletion ensures that any snapshots or snapshot-related virtual volumes that are part of the VM, such as the snapshot virtual volume, do not interfere with stopping of the test failover.

You can create full clones of the test VMs.

You can create fast clones only if the policy applied to the new VM contains the same replication group ID as the VM being cloned. Attempts to place the child VM outside of the replication group of the parent VM fail.